Chris tucker posted a thread "how to dominate your local search" I went down the listing, and just blew it up. Everything I could post my info on I did. Some of these sites are a PAIN to get your stuff on, but they typically have a higher page rank, which allow customers to find me, if they don't find my website.
I signed up a fews years back to dump some keywords and get a few backlinks. First and only time I have ever been there. Started getting a ton of Yelp spam e-mails after that.